The present invention relates to a steam unit with external fastening, including a tank for frothing milk or heating beverages, for a machine for espresso beverages.
External steam units for frothing milk for use in a machine for espresso beverages are known in the art. Espresso beverages typically include espresso coffee.
In general said known units have problems of reliability due to possible clogging of the steam output circuit, caused by interaction with the milk, or safety problems due to the pressure of steam or, to the presence of electrical circuits which could interact with the steam or with the milk, or problems related to the difficulty in cleaning them, caused by difficult access to the parts which must be kept clean.
These problems may arise for example in cases where in a container for frothing milk, the frothing occurs in the bottom side of the container, as for example disclosed in documents GB-382972 or FR-769848.
Document WO-01/97668 discloses a container for frothing milk, having an inlet in the bottom for receiving steam from a base; a tube is connected to the inlet in the bottom for bringing the steam to the internal bottom part of the container, where a second tube brings air from the top for heating and frothing the milk: this also creates problems as described above. Additional problems arise for cleaning the terminals of the tubes: in fact the container must be emptied before cleaning. Moreover, frothing the milk in the bottom does not allow milk as such to be maintained separated from froth in the bottom part of the container.